


Experiment

by Kasen



Category: Voltron: Legendary Defender
Genre: M/M, Multiple Orgasms, Trans!Keith, Vaginal Fingering
Language: English
Status: Completed
Published: 2018-09-22
Updated: 2018-09-22
Packaged: 2019-07-15 10:00:10
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,374
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16060778
Author URL: https://archiveofourown.org/users/Kasen/pseuds/Kasen
Summary: Keith and Shiro explore the sexual prowess of Shiro's prosthetic arm.





	Experiment

Keith frowned profusely as Shiro wiggled his eyebrows at him from across the room. The other was being surprisingly suggestive given their current set of circumstances. Shiro was in the middle of a unit-wide presentation for the Galaxy Garrison, and Keith was asked to join him and listen in. He had been bored every time someone who wasn’t Shiro spoke. He didn’t understand why the other had implored he come in to hear the same conversations he had heard several times in the past, both with team Voltron, and in private with Shiro as well.

 _What do you have up your sleeve?_ Keith wondered as he chose to ignore another monotonous lieutenant discuss something Keith already knew about the Galra Empire. Shiro was eying him as well, a small smile curling the corner of his lips in a cattish grin.

Keith swallowed hard. A thought struck him as he observed the other’s missing prosthetic.

_Oh God._

Keith pressed his lips in a hard line and squeezed his legs tightly together. When Shiro was first asked about his arm as he entered the boardroom, he answered with a nonchalant shrug, stating that he left it in his room to recharge. Nobody from the Garrison had questioned him. Only Keith and Coran knew his arm didn’t need to recharge. It was strange, but neither cared to understand his true intentions.

Until now.

Keith inhaled sharply as he realized that he was _meant_ to be bored. He was meant to excuse himself from the meeting and mosey his way into Shiro’s room. The other had totally planned to make his mandatory day-long meeting worth his while, and he had playfully teased Keith into helping him get through it.

“Excuse me,” Keith said after clearing his throat and standing. Everyone looked at him, surprised that he had interrupted a rather heated discussion. “My squad is calling me. Shiro has already briefed me on the key points of this meeting. I’ll follow up with anything I might have missed as soon as I can.”

“Y-you can’t just leave,” a commanding chief sputtered in dismay, undoubtedly unaccustomed to a young adult a third of his age making his own decisions and implying he knew all that he needed to.

“It’s fine,” Shiro dismissed with a knowing smile. “It’s true. I told Keith coming here wasn’t mandatory and that he could leave whenever he saw fit.”

Keith didn’t bother adding to his response. Instead, he apologized for interrupting and quickly made his leave. His heart was racing. Despite only discovering Shiro’s plan a few minutes ago, his body was already reacting. His stomach churned in anticipation and his lips quivered with excitement. The moment he entered Shiro’s room, he hastily locked the door and made a beeline for the other’s mattress. Shiro’s prosthetic arm lay still on the comforter until Keith sat near it. He reached over and intertwined his fingers between Shiro’s, and smiled gently when the other responded, the cold digits holding onto Keith firmly.

This wasn’t the first time Shiro had remotely used his arm for something outside of attacking or defending himself and those in danger. He and Keith discussed the properties of his arms well into the nights as they became reacquainted with living on Earth. Their experiments started small. _Can you use it at a very large distance? Can you feel what you’re doing? Do you have control over it?_ The questions were answered after days of discreet testing. Sometimes Shiro grasped Keith’s hand with his prosthetic one and told him to walk as far as he could before he lost function —the indicator being that of when he was no longer rubbing his thumb along Keith’s hand. Sometimes, he’d separate himself from his arm and ask Keith to find it at his own leisure, the timing of locating his prosthetic out the window and only touch being the dependent variable. Whether Shiro reacted to said touch was the independent variable.

Keith brought the prosthetic to his lips and kissed Shiro’s knuckles. Their hypotheses were fun tests that came back with conclusive results. Shiro had incredible control of his arm at a tremendous distance, and his sensors seemingly heightened the further away he was. The arm was meant to be within his reach; and the two learned that Shiro could detect it —almost like a beacon— when he was separated from it.

Despite Shiro being intrigued by the revelation of his new arm, Keith was a little less focused on the science, and more so interested in the potential… _sexual_ prospects. Luckily for him; Shiro caught on quickly. They became more experimental in bed. They performed certain acts in bed that other couples could only dream of trying.

Keith fumbled with his pants as he rested Shiro’s arm on his thigh. After removing the trousers, he backed further onto Shiro’s mattress and lay down. Shiro didn’t need Keith’s help. Despite there being several walls between him and his arm, he controlled it like he was lying right there next to Keith. He ran his fingers along Keith’s inner thigh, and teased the space between his leg and pussy. Keith shuddered as the other slowly worked his way closer and closer to the middle, and arched his back when Shiro finally ran a single digit between the wet lips staining the fabric of his underwear.

 _“Oh,”_ Keith moaned helplessly. He grasped the pillow cushioning his head with both hands, desperate to restrain himself and allow Shiro to do all the work. If the other was going to be stuck in a boring meeting all day, he needed to make it last.

Keith focused on his breathing as Shiro worked him over slowly. He continued sliding a digit between Keith’s legs until Keith was completely wet. He shuddered every time the other got painstakingly close to his clit, and sighed —almost in frustration— when the other backed away from coming into contact with it. Seconds turned into minutes. Keith’s faced was flushed and sweat was beginning to pepper his skin.

Eventually, Shiro’s movements came to a halt. Keith waited a beat to see if the other would continue, and after a minute, he moved again, but not in the way Keith was expecting. Shiro caressed Keith’s thigh and pressed forward, sliding two of his fingers beneath Keith’s sodden underwear.

Keith gasped and bulked at the sudden contact. He moaned long and low as Shiro guided the pads of his prosthetic fingers between his legs and into the dilated entrance. The pain was welcomed if not unexpected. Despite taking much more of Shiro in the past, the two hadn’t had the time to make love in the recent days. _Two weeks,_ Keith reminded himself. Every night was torture when it wasn’t with Shiro lying heavily on top on him and stretching him open with his member. Every night was torture when it wasn’t with Shiro holding him close and teasing accusations at him about whatever trouble Team Voltron might have caused the Garrison or Atlas crew that day.

Keith whimpered as the other thrusted his fingers into and out of Keith in deep, even rhythms. The slick sounds of his muscles being stretched apart and his natural fluids spreading wherever gravity took them filled the silence of the room. Keith’s breathing became much louder. His rhythmic panting hiccupped when Shiro added a third finger, and he lost any hope of regaining cadence as his moans overwhelmed the sounds of his gasping.

“F-fuck,” Keith mumbled. He loved every second of this. His hips canted forward and back to match Shiro’s movements, and he shuddered restlessly when the other pulled out to rub the discharge along his labia.

Keith was expecting Shiro to drag this out until he was numb and raw from the stimulation —so when the low buzz of Shiro’s arm added to the sounds of Keith’s panting, he knew he was in for a quick orgasm.

Keith cried out in pleasure as Shiro ran a finger along his clit. As if the mere contact wasn’t overwhelming enough, Shiro had activated his arm’s electron barrier —a function that caused his arm to vibrate at abnormal speeds in order to reduce the effects of particle dissasemblers. It was a defensive mechanism from a highly advanced prosthetic arm that Shiro had turned into a _sex toy_ for Keith.

Keith loved it.

He convulsed when Shiro returned two of his fingers within him, and had now — _thank goodness_ , guided a thumb to circle over and around his clit, all of which were vibrating at overwhelming speeds. Keith twitched and moaned contently as he was fucked through his underwear. He tried to keep himself as still as possible, back on the mattress and hands out of Shiro’s way; but the urge to sit up was astounding. Shiro was hitting him where he knew would feel good to Keith, but not enough to push him into climax. Keith endure only a minute more of the delightful teasing before he lost his self-control and sat up. Grabbing Shiro’s forearm with both hands, Keith started thrusting his pelvis forward and back, fucking himself with the help of Shiro’s fingers. He could only keep up his animalistic grinding for another minute before the rising climb of his orgasm hit its peak and came crashing down on him like icy water in a warm summer day. Keith cried out and convulsed over Shiro’s arm; his entire body spasming as he rode out his orgasm.

Keith didn’t have time to catch his breath when Shiro came rushing into the bedroom. Despite his stoic demeanor, Keith knew the other was barely controlling himself. His cheeks were rosy, and his forehead was slick with sweat. Shiro had pulled himself out of the meeting to see Keith, which showed that he too could barely handle the two weeks without his lover.

“Hi Takashi,” Keith breathed dreamily as he let go of the other’s arm.

“Hi baby,” Shiro whispered, his prosthetic floating back into place. Shiro glanced down at his fingers, eyes scrutinizing the webbed discharge stretching between his metallic digits. “Did you come?”

“Yeah,” Keith sighed. He opened his legs for Shiro, allowing the other to inspect the slickness coating his thighs and staining his underwear and blankets beneath.

“I don’t have long,” Shiro croaked as he crawled onto the bed, head hovering between Keith’s legs. “I don’t know where to begin with you.”

Keith removed his tarnished underwear and the two moaned for different reasons, Keith in anticipation for whatever the spark in Shiro’s eyes suggested, and Shiro in unchaste hunger as he eyed the strings of Keith’s wetness sticking to the fabric and stretching long and far as he threw it over the side of his mattress.

“Take off your shirt,” Shiro instructed. Keith hastily did as he was told, and his cunt throbbed with excitement as Shiro did the same. Shiro guided Keith onto his lap, and the two moaned in pleasure; back pressed to chest, as Shiro began playing with Keith.

“I thought you said you don’t have long,” Keith breathed. Shiro was using his left hand this time; the warm, calloused fingers circling the lips of his vagina and pressing the folds against his clitoris.

“I can handle the glares if it means hearing you come for me,” Shiro purred against Keith’s ear. Keith moaned happily. Shiro was well aware of his inhuman recovery time. Keith was already on his second climb to orgasm, and all it took was a few fingers.

“Love you so much,” Keith murmured blissfully. “Oh _god_ Shiro, I love it when you do this to me.”

“Love you too, baby. You deserve to feel good,” Shiro muttered in response. He kissed and sucked the shell of Keith’s ear, and guided his slick prosthetic hand onto the crook of Keith’s neck to hold him steady while fingering him relentlessly.

 _“Fuck—”_ Keith gasped. _“—yes!”_ he could no longer form a coherent sentence. Shiro was pushing into him with almost violent urgency. Keith’s hips snapped forward to meet the fingers pushing him closer to the edge. _“Oooh,_ Takashi — _ah…”_

“You’re so good to me, Keith.”

Shiro sounded like he hadn’t just come out of a meeting to fuck his partner with the intentions of returning back. Keith moaned harder at the thought of Shiro washing his hands and returning to a presentation no one knew he pulled away from to finger Keith relentlessly.

_No one would know._

_“Shi—t,”_ Keith mewled. This was the third time they had done this. People were giving them strange looks. Coran flat out grimaced with Keith excused himself, implying he _knew._ Keith was now smiling to himself, cheeks scarlet with shame and pleasure as he pushed aside his memories.

“Fuck,” he moaned. The sound of skin slapping into and against slick skin sent his mind whirling.

“So good,” Shiro mumbled into his ear, over and over again between chaste kisses against his brow.

“God,” Keith managed to sigh before he started twitching again. His second orgasm rocked his body harder than his first. Maybe it was because he wanted to put on a show for Shiro, or maybe it was because the other was coming with him, the spasms of Shiro’s thighs shaking Keith viciously. Regardless, Keith saw stars and then nothing. His eyes fluttered shut as he attempted to catch his breath. He was weak from climaxing twice, and allowed Shiro to place him gently onto his mattress and clean him with his sodden blanket.

“Wish I could stay, baby,” Shiro managed between hungry kisses against Keith’s lips.

“Duty calls,” Keith grinned. “Go wash up before someone notices the smell on your fingers.”

Shiro pressed his index and middle finger into Keith’s mouth, and Keith obediently lapped his tongue around the digits, tasting himself.

“Shit, okay. I’m leaving. I’m leaving before this escalates again.”

Keith snorted but didn’t try anything else that might be suggestive to his easily-roused boyfriend. He watched Shiro enter the bathroom, wash what he needed to, and dress himself in his uniform before coming back out to give Keith a yearning gaze.

“Go,” Keith insisted. Shiro nodded, pressed one final kiss against Keith’s temple, and fled his bedroom, leaving Keith flushed and satisfied.

**Author's Note:**

> [The piece of art that ruined me.](https://twitter.com/pejaposarambi/status/1043266116473298944) Thank you Andy for satisfying my thirst :')
> 
> @Kroligane


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